Azo dyes for thermotransfer printing

ABSTRACT

Azo dyes useful for thermotransfer printing have the formula &lt;IMAGE&gt; I

The present invention relates to the use in thermotransfer printing ofazo dyes of the formula I ##STR2## where the substituents have thefollowing meaning: R¹ is hydrogen;

C₁ -C₁₅ -alkyl which may be substituted by phenyl or phenoxy;

cyclohexyl which may be substituted by C₁ -C₅ -alkyl, C₁ -C₅ -alkoxy orhalogen;

phenyl which may be substituted by C₁ -C₅ -alkyl, C₁ -C₅ -alkoxy,sulfonamido or halogen;

thienyl which may be C₁ -C₅ -alkyl- or halogen-substituted, furanyl orpyridyl;

a radical of the formula II

    [--W--O].sub.n --R.sup.4                                   II

where

W is identical or different C₂ -C₆ -alkylene,

n is from 1 to 6 and

R⁴ is C₁ -C₄ -alkyl or a phenyl or benzyl group which may both besubstituted by C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy;

R² and R³ are each hydrogen;

alkyl, alkoxy, alkoxyalkyl, alkanoyloxyalkyl, alkoxycarbonyloxyalkyl,alkoxycarbonylalkyl, haloalkyl, hydroxyalkyl or cyanoalkyl, which mayeach contain up to 15 carbon atoms and be substituted by phenyl, C₁ -C₄-alkylphenyl, C₁ -C₄ -alkoxyphenyl, halophenyl, benzyloxy, C₁ -C₄-alkylbenzyloxy, C₁ -C₄ -alkoxybenzyloxy, halogenzyloxy, halogen,hydroxyl or by cyano; cyclohexyl which may be substituted by C₁ -C₁₅-alkyl, C₁ -C₁₅ -alkoxy or halogen;

phenyl which may be substituted by C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkoxy,benzyloxy or halogen; a radical of the abovementioned formula II; and

is the radical of a diazo component III

    D--NH.sub.2                                                III

and specifically to a process for transferring these azo dyes bydiffusion from a transfer to a plastic-coated substrate with the aid ofa thermal printing head.

The technique of thermotransfer printing is common knowledge; suitableheat sources besides lasers and IR lamps are in particular thermalprinting heads capable of emitting short heat pulses lasting fractionsof a second.

In this preferred embodiment of thermotransfer printing, a transfersheet which contains the transfer dye together with one or more binders,a support material and possibly further assistants such as releaseagents or crystallization inhibitors is heated from the back with thethermal printing head, causing the dye to migrate out of the transfersheet and to diffuse into the surface coating of the substrate, forexample into the plastic coat of a coated sheet of paper.

The essential advantage of this process is that the amount of dye to betransferred (and hence the color gradation) can be controlled in aspecific manner via the amount of energy supplied to the thermalprinting head.

Thermal transfer printing is in general carried out using the threesubtractive primaries yellow, magenta and cyan (with or without black),and the dyes used must have the following properties to ensure optimalcolor recording: ready thermal transferability, little tendency tomigrate within or out of the surface coating of the receiving medium atroom temperature, high thermal and photochemical stability, and alsoresistance to moisture and chemicals, no tendency to crystallize onstorage of the transfer sheet, a suitable hue for subtractive color thetransfer sheet, a suitable hue for subtractive color mixing, a highmolar absorption coefficient, and ready industrial availability.

It is very difficult to meet all these requirements at one and the sametime. In particular, the magenta dyes used to date have not been fullysatisfactory. This is also true for example of the azo dyes described,and recommended for thermal transfer, in U.S. Pat. No. 4,764,178, whichresemble the azo dyes I and have coupling components based on aniline,tetrahydroquinoline, aminoquinoline or julolidine.

The azo dyes I themselves are known per se or obtainable by knownmethods, for example as described in earlier German Patent Application P38 33 443.7, O. Annen et al., Rev. Prog. Coloration 17 (1987), 72-85, orM. A. Weaver and L. Shuttleworth, Dyes and Pigments 3 (1982), 81-121.

It is an object of the present invention to find suitable red and bluedyes for thermotransfer printing which come closer to the requiredproperty profile than the prior art dyes.

We have found that this object is achieved by the azo dyes I defined atthe beginning.

We have also found a process for transferring azo dyes by diffusion froma transfer to a plastic-coated substrate with the aid of a thermalprinting head, which comprises using for this purpose a transfer onwhich are situated one or more of the azo dyes I defined at thebeginning.

We have further found preferred embodiments of this process, whichcomprise using dyes of the formula Ia ##STR3## where the substituentshave the following meanings: R^(1') is C₁ -C₈ -alkyl which may besubstituted by phenyl or cyclohexyl;

phenyl which may be substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy orchlorine;

thienyl;

a radical of the formula IIa

    [--(CH.sub.2).sub.3 --O].sub.p --(CH.sub.2).sub.2 --O].sub.q --R.sup.31 IIa

where p is 0 or 1, q is from 1 to 4, and R^(4') is C₁ -C₄ -alkyl, phenylor benzyl;

R^(2') and R^(3') are each C₁ -C₁₂ -alkyl, C₁ -C₁₀ -alkoxy or C₁ -C₁₀-cyanoalkyl or a radical of the abovementioned formula IIa; and

D' is the radical of a diazo component III of the aniline,phenylazoaniline, aminothiophene, phenylazoaminothiophene,aminothiazole, phenylazoaminothiazole, aminoisothiazole,aminobenzisothiazole, aminothiadiazole, aminoisothiadiazole,aminooxazole, aminooxadiazole, aminodiazole, aminotriazole oraminopyrrole series.

Preferred diazo components III are:

aniline derivatives of the formula IIIa ##STR4## phenylazoanilinederivatives of the formula IIIb ##STR5## aminothiphene derivatives ofthe formula IIIc ##STR6## phenylazoaminothiophene derivatives of theformula IIId ##STR7## aminothiazole derivatives of the formula IIIe##STR8## phenylazoaminothiazole derivatives of the formula IIIf ##STR9##aminoisothiazole derivatives of the formula IIIg ##STR10##aminobenzisothiazole derivatives of the formulae IIIh and IIIi ##STR11##aminothiadiazole derivatives of the formula IIIk ##STR12##aminoisothiadiazole derivatives of the formula IIIl ##STR13##aminopyrrole derivatives of the formula IIIm ##STR14##

Here the substituents have the following meanings:

R⁵, R⁶ and R⁷ are each hydrogen, chlorine, bromine, nitro or cyano;alkyl, alkoxyalkyl, alkanoyloxyalkyl or alkoxycarbonylalkyl, which mayeach contain up to 10 carbon atoms;

a radical of the formula II;

a radical of the formula --CO--OR¹⁵, --CO--NR¹⁵ R¹⁶, --SO--OR¹⁵, --SO₂--OR¹⁵ or --SO₂ --NR¹⁵ R¹⁶ in which

R¹⁵ and R¹⁶ are each alkyl or alkoxyalkyl which may each contain up to10 carbon atoms, and

R¹⁶ may also be hydrogen;

R⁵ may also be oxadiazole substituted in the 3-position by C₁ -C₈-alkoxy;

R⁶ may also be a radical of the formula --CO--R¹⁷ or --CO--OR¹⁷ where

R¹⁷ is phenyl which may be substituted by C₁ -C₈ -alkyl;

a radical of the formula IV ##STR15## where X is cyano, --CO--OR¹⁵ or--CO--NR¹⁵ R¹⁶ ;

R⁸ is hydrogen, chlorine, cyano or thiocyanato, alkyl, alkoxy, alkylthioor alkoxyalkyl which may each contain up to 10 carbon atoms; 2-(C₁ -C₂-alkoxycarbonyl)ethylthio; 2-(pyrrolid-1-yl)ethyl; C₅ -C₆ -cycloalkyl or-cycloalkylthio; phenyl which may be substituted by C₁ -C₄ -alkyl, C₁-C₄ -alkoxy, benzyloxy or phenylthio; Ar-C₁ -C₄ -alkythio; Ar-C₁ -C₄-alkoxy or Ar-C₁ -C₄ -alkylthio;

thienyl or pyridyl which may each be substituted by C₁ -C₄ -alkyl;

a radical of the formula II;

a radical of the formula --CO--OR¹⁵, --CO--NR¹⁵ R¹⁶, --SO--OR¹⁵ or --SO₂--OR¹⁵ ;

R⁹ is hydrogen, chlorine, bromine, nitro, cyano, thiocyanato or phenyl;or a radical of the formula --CO--OR¹⁵ or --CO--NR¹⁵ R¹⁶ ;

R¹⁰ is hydrogen, chlorine, bromine, nitro, cyano or formyl; a radical ofthe formula --CO--OR¹⁵ or --CO--NR¹⁵ R¹⁶ ; or a radical of the formulaIV

R¹¹ and R¹² are each hydrogen, chlorine, bromine, nitro or cyano; C₁ -C₄-alkyl or C₁ -C₄ -alkoxy; or a radical of the formula --CO--OR¹⁵ or--CO--NR¹⁵ R¹⁶ ;

R¹³ is hydrogen, chlorine, bromine or C₁ -C₄ -alkyl;

R¹⁴ is hydrogen or cyano; or a radical of the formula --CO--OR¹⁵ or--CO--NR¹⁵ R¹⁶ ;

R¹⁸ is cyano or formamido;

R¹⁹ is methyl or phenyl;

X is hydrogen, chlorine or nitro; and

Y is hydrogen or cyano.

Suitable alkyl R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R¹¹, R¹², R¹³, R¹⁵ or R¹⁶is in particular methyl, ethyl, propyl, isopropyl or butyl, but alsoisobutyl, sec.-butyl or tert.-butyl.

R¹, R², R³, R⁵, R⁶, R⁷, R⁸, R¹⁵ and R¹⁶ may each also be for examplepentyl, isopentyl, neopentyl, tert.-pentyl, hexyl, 2-methylpentyl,heptyl, octyl, 2-ethylhexyl, mixed isooctyl isomer and cyclohexyl.

R¹, R², R³, R⁵, R⁶, R⁷, R⁸, R¹⁵ and R¹⁶ may each also be for examplenonyl, decyl, mixed isononyl isomer or mixed isodecyl isomer.

Other possible meanings for R¹, R² and R³ include undecyl, dodecyl,tridecyl, mixed isotridecyl isomer, tetradecyl and pentadecyl and for R²and R³ additionally hexadecyl, heptadecyl, octadecyl, nonadecyl andeicosyl.

Alkyls R² and R³ may each also be substituted by phenyl; specificexamples, where Ph=phenyl, are:

--CH₂ --Ph, --CH(CH₃)--Ph, --(CH₂)₂ --Ph,

--(CH₂)₄ --CH(CH₃)--Ph--3--CH₃,

--(CH₂)₃ --CH(C₄ H₉)--Ph--3--CH₃,

--(CH₂)₆ --Ph-4--O--CH₃,

--CH(C₂ H₅)--(CH₂)₃ --Ph--3--O--C₂ H₅ and

--CH(C₂ H₅)--(CH₂)₃ --Ph--3--Cl.

It is also possible to use for example the following halo, hydroxyl andcyanoalkyl groups as R² or R³ :

--(CH₂)₅ --Cl, --CH(C₄ H₉)--(CH₂)₃ --Cl or --(CH₂)₄ --CF₃ ;

--(CH₂)₂ --CH(CH₃)--OH, --(CH₂)₂ --CH(C₄ H₉)--OH oder CH(C₂ H₅)--(CH₂)₉--OH;

--(CH₂)₂ --CN, --(CH₂)₃ --CN, --CH₂ --CH(CH₃)--CH(C₂ H₅)--CN, --(CH₂)₆--CH(C₂ H₅)--CN and

--(CH₂)₃ --CH(CH₃)--(CH₂)₂ --CH(CH₃)--CN.

When R¹, R², R³, R⁵, R⁶, R⁷, R¹⁵ or R¹⁶ is alkoxyalkyl of preferredformula II, suitable W is for example 1,2- and 1,3-propylene, 1,2-,1,3-, 1,4- and 2,3-butylene, pentamethylene, hexamethylene and2-methylpentamethylene, but in particular ethylene, and R⁴ is inparticular methyl, ethyl, propyl, butyl and also benzyl and phenyl whichmay each be substituted by methyl(oxy), ethyl(oxy), propyl(oxy) orbutyl(oxy). Particularly preferred II is for example:

--(CH₂)₂ --O--CH₃, --(CH₂)₂ --O--C₂ H₅, --(CH₂)₂ --O--C₃ H₇, --(CH₂)₂--O--C₄ H₉,

--(CH₂)₂ --O--CH₂ --CH(CH₃)--CH₃,

--(CH₂)₂ --O--Ph, --(CH₂)₂ --O--CH₂ --Ph,

--[(CH₂)₂ --O]₂ --CH₃, --[(CH₂)₂ --O]₂ --C₂ H₅, --[(CH₂)₂ --O]₂ --Ph,

--[(CH₂)₂ --O]₂ --Ph--4--O--C₄ H₉,

--[(CH₂)₂ --O]₃ --C₄ H₉, --[(CH₂)₂ --O]₃ --Ph, --[(CH₂)₂ --O]₃--Ph--3-C₄ H₉,

--[(CH₂)₂ --O]₄ --CH₃,

--(CH₂)₃ --O--(CH₂)₂ --O--CH₃, --(CH₂)₃ --O--(CH₂)₂ --O--C₂ H₅,

--(CH₂)₃ --O--(CH₂)₂ --O--Ph, --(CH₂)₃ --O--[(CH₂)₂ --O]₂ --CH₃ and

--(CH₂)₃ --O--[(CH₂)₂ --O]₂ --C₂ H₅.

Further preferred groups II are for example:

--(CH₂)₃ --O--CH₃, --(CH₂)₃ --O--C₂ H₅, --(CH₂)₃ --O--C₃ H₇, --(CH₂)₃--O--C₄ H₉,

--(CH₂)₃ --O--Ph, --[(CH₂)₃ --O]₂ --CH₃, --[(CH₂)₃ --O--]₂ --C₂ H₅,

--CH₂ --CH(CH₃)--O--CH₃, --CH₂ --CH(CH₃)--O--C₂ H₅, --CH₂--CH(CH₃)--O--C₃ H₇,

--CH₂ --CH(CH₃)--O--C₄ H₉, --CH₂ --CH(CH₃)--O--Ph,

--(CH₂)₄ --O--CXH₃, --(CH₂)₄ --O--C₂ H₅, --(CH₂)₄ --O--C₄ H₉,

--(CH₂)₄ --O--CH₂ --CH(C₂ H₅)--C₄ H₉, --(CH₂)₄ --O--Ph,

--(CH₂)₄ --O--CH₂ --Ph--2--O--C₂ H₅, --(CH₂)₄ --O--C₆ H₁₀ --2--C₂ H₅,

--[(CH₂)₄ --O]₂ --CH₃, --[(CH₂)₄ --O]₂ --C₂ H₅, --[(CH₂)₂ --CH(CH₃)--O]₂--C₂ H₅,

--(CH₂)₅ --O--CH₃, --(CH₂)₅ --O--C₂ H₅, --(CH₂)₅ --O--C₃ H₇, --(CH₂)₅--O--Ph,

--(CH₂)₂ --CH(C₂ H₅)--O--CH₂ --Ph--3--O--C₄ H₉, --(CH₂)₂ --CH(C₂H₅)--O--CH₂ --Ph--3--Cl,

--(CH₂)₆ --O--C₄ H₉, --(CH₂)₆ --O--Ph--4--O--C₄ H₉, --(CH₂)₃--CH(CH₃)--CH(CH₃)--CH₂ --O--C₄ H₉,

--(CH₂)₃ --O--(CH₂)₄ --O--CH₃, --(CH₂)₃ --O--(CH₂)₄ --O--C₂ H₅,

--(CH₂)₄ --O--(CH₂)₃ --O--CH₃ and --(CH₂)₄ --O--(CH₂)₃ --O--C₂ H₅.

Suitable alkoxyalkyl also includes for example:

--(CH₂)₈ --O--CH₃, --(CH₂)₈ --O--C₄ H₉, --(CH₂)₈ --O--CH₂ --Ph-3--C₂ H₅,

--(CH₂)₄ --CH(Cl)--(CH₂)₃ --O--CH₂ --Ph--3--CH₃ and

--(CH₂)₃ --CH(C₄ H₉)--O--CH₂ --Ph--3--CH₃.

Of the above-recited alkoxyalkyl groups, those which contain up to 8carbon atoms are also suitable for use as R⁸ and those having up to 12carbon atoms are also suitable for use as R¹⁵ and R¹⁶.

Preferred alkoxy R², R³, R⁸, R¹¹ or R¹² is for example methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy or sec.-butoxy.

R⁸ and especially R² and R³ may each also be for example pentyloxy,isopentyloxy, neopentyloxy, hexyloxy, oxtyloxy or 2-ethylhexyloxy.

R² and R³ may each in addition be for example nonyloxy or decyloxy butalso undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy orpentadecyloxy.

R⁸ may also be alkylthio, such as preferably methylthio, ethylthio or2-cyanoethylthio, but also propylthio, isopropylthio, butylthio,pentylthio, hexylthio, heptylthio, octylthio, 2-ethylhexylthio,2-ethoxycarbonylethylthio or in particular 2-methoxycarbonylthio.

Suitable alkanoyloxyalkyl, alkoxycarbonyloxyalkyl or alkoxycarbonylalkylR² or R³ is for example:

--(CH₂)₂ --O--CO--CXH₃,

--(CH₂)₃ --O--CO--(CH₂)₇ --CH₃,

--(CH₂)₂ --O--CO--(CH₂)₃ --PH-2--O--CH₃,

--CH(CH₂ --Ph--3-CH₃)--O--CO--C₄ H₉ and

--(CH₂)₄ --O--CO--(CH₂)₄ --CH(C₂ H₅)--OH;

--(CH₂)₂ --O--CO--O--CH₃,

--(CH₂)₃ --O--CO--O--(CH₂))₇ --CH₃,

--CH(C₂ H₅)--CH₂ --O--CO--O--C₄ H₉,

--(CH₂)₄ --O--CO--O--(CH₂)₂ --CH(CH₃)--O--Ph--3--CH₃ and

--(CH₂)₅ --O--CO--O--(CH₂)₅ --CN;

--(CH₂)₂ --CO--O--CH₃,

--(CH₂)₃ --CO--O--C₄ H₉,

--(CH₂)₃ --CH(CH₃)--CH₂ --CO--O--C₄ H₉,

--(CH₂)₃ --CH(C₄ H₉)--CH₂ --CO--O--C₂ H₅,

--(CH₂)₂ --CO--O--(CH₂)₅ --Ph,

--(CH₂)₄ --CO--O--(CH₂)₄ --Ph--4--C₄ H₉,

--(CH₂)₃ --CO--O--(CH₂)₄ --O--Ph-3---O--CH₃,

--(CH₂)₂ --CH(CH₂ OH)--(CH₂)₂ --CO--O--C₂ H₅,

--CH(C₂ H₅)--CH₂ --CO--O--(CH₂)₄ --OH and

--(CH₂)₃ --CO--O--(CH₂)₆ --CN.

Phenyl and cyclohexyl which may each be present as R¹, R² or R³ are forexample: --Ph, --Ph--3--CH₃, --Ph--4--(CH₂)₁₀ --CH₃, --Ph--3--(CH₂)₅--CH(CH₃)--CH₃, Ph--4--O--C₄ H₉, --Ph--4--(CH₂)₅ --CH(C₂ H₅)--CH₃,--Ph--4--O--CH₂ --Ph or --Ph--4--Cl and also in the case of R¹ inparticular --Ph--3--SO₂ --N(CH₃)--CH₃ or Ph--3--SO₂ --N--((CH₂)₂--O--CH₃)--(CH₂)₂ --O--CH₃ ; --C₆ H₁₀ --4--CH₃, --C₆ H₁₀ --4--C₁₀ H₂₁,--C₆ H₁₀ --3--O--C₄ H₉, --C₆ H₁₀ --3--O--(CH₂)₄ --CH(C₂ H₅)--CH₃ or --C₆H₁₀ --4--Cl.

Where R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹² or R¹⁴ is a group of the formula--CO--OR¹⁵ or --CO--NR¹⁵ R¹⁶, particularly suitable instances thereofare --CO--O--CH₃, --CO--O--C₂ H₅, --CO--O--C₃ H₇, --CO--O--C₄ H₉,--CO--N(CH₃)--CH₃ and --CO--N(C₂ H₅)--C₂ H₅, but also for example--CO--O--C₅ H₁₁, --CO--O--C₆ H₁₃, --CO--n(C₃ H₇)--C₃ H₇ and --CO--n(C₄H₉.

Groups of the formula --SO--OR¹⁵ or --SO₂ --OR¹⁵, which may each be usedas R⁵, R⁶, R⁷ or R⁸ are for example:

--SO--O--CH₃, --SO--O--C₂ H₅, --SO--O--C₃ H₇,

--SO₂ --O--CH₃, --SO₂ --O--C₂ H₅, --SO₂ --O--C₃ H₇.

R⁵, R⁶ and R⁷ may each also be groups of the formula --SO₂ --NR¹⁵ R¹⁶,in particular --SO₂ --N(CH₃)--CH₃, --SO₂ --N((CH₂)₂ --O--CH₃)--(CH₂)₂--O--CH₃, but also for example --SO₂ --N(C₂ H₅)--C₂ H₅ or --SO₂ --N(C₃H₇)--C₃ H₇.

R⁶ and R¹⁰ may each also be groups of the formula IV, such as--CH═C(CN)--CN, --CH═C(CN)--CO--O--CH₃, --CH═C(CN)--CO--O--C₂ H₅,--CH═C(CN)--CO--O--C₃ H₇, --CH═C(CN)--CO--O--C₄ H₉,--CH═C(CN)--N(CH₃)--CH₃ or --CH═C(CN)--N(C₂ H₅)--C₂ H₅.

Of the aforementioned radicals, R¹ is particularly preferably C₁ -C₈-alkyl, especially methyl or isopropyl, cyclohexyl, phenyl, which mayalso be methoxy-, sulfonamido- or chlorine-substituted, or benzyl.Preferred R¹² further includes 3-thienyl and especially 2-thienyl,3-furanyl and especially 2-furanyl, and also 2-pyridyl, 4-pyridyl andespecially 3-pyridyl.

Preferred alkyl R² or R³ is of up to 12 carbon atoms, especially methyl,ethyl or propyl, preferred cyanoalkyl and alkoxy R² or R³ is of up to 10carbon atoms. Particularly preferred R² and R³ each has the formula IIawith methyl or ethyl as R^(4').

Of the above-recited diazo components D-NH₂, the following areparticularly preferred:

aniline derivatives IIIa having the above-defined meanings of R⁵, R⁶ andR⁷

aminothiophene derivatives IIIc having the following meanings for R⁸, R⁹and R¹⁰ :

R⁸ is hydrogen or chlorine; alkyl, alkoxy or alkoxyalkyl, which may eachcontain up to 8 carbon atoms; phenyl which may be C₁ -C₄ -alkyl- or C₁-C₄ -alkoxy-substituted, or benzyl; or a radical of the formula--CO--OR¹⁵ ;

R⁹ is cyano or a radical of the formula --CO--OR¹⁵ or else --CO--NR¹⁵R¹⁶ ; and

R¹⁰ is cyano, nitro, formyl or a radical of the formula IV

aminothiazole derivatives IIIe having the following meanings for R⁸ andR¹⁰ :

R⁸ is hydrogen, chlorine, C₁ -C₈ -alkyl, phenyl which may be C₁ -C₄-alkyl- or C₁ -C₄ -alkoxy-substituted, benzyl, or a radical of theformula --CO--OR¹⁵ ; and

R¹⁰ is cyano, nitro, formyl or a radical of the formula --CO--OR¹⁵

aminoisothiazole derivatives IIIg having the following meanings for R⁸and R⁹ :

R⁸ is chlorine, alkyl, alkoxy, alkylthio or alkoxyalkyl which may eachcontain up to 8 carbon atoms, phenyl which may be C₁ -C₄ -alkyl- or C₁-C₄ -alkoxy-substituted, benzyl or benzyloxy, and

R⁹ is cyano, nitro or a radical of the formula --CO--OR¹⁵

aminothiadiazole derivatives IIIk and aminoisothiadiazole derivativesIIIl having the following meaning for R⁸ :

R⁸ is hydrogen, chlorine, cyano, thiocyanato, or alkyl, alkoxy,alkylthio or alkoxyalkyl, which may each contain up to 8 carbon atoms,2-(C₁ -C₂ -alkoxycarbonyl)ethylthio, phenyl which may be C₁ -C₄ -alkyl-or C₁ -C₄ -alkoxy-substituted, benzyl, benzyloxy, or a radical of theformula --CO--OR¹⁵, --SO--OR¹⁵ or --SO₂ --OR¹⁵.

The dyes I to be used according to the present invention are notable forthe following properties compared with prior art red and bluethermotransfer printing dyes having aniline-based coupling components:readier thermal transferability, improved migration properties in thereceiving medium at room temperature, higher thermal stability, higherlightfastness, better resistance to moisture and chemicals, bettersolubility in printing ink preparation, higher color strength, andreadier industrial accessability.

In addition, the azo dyes I exhibit a distinctly better purity of hue,in particular in mixtures of dyes, and produce improved black prints.

The transfer sheets required as dye donors for the thermotransferprinting process according to the present invention are prepared asfollows. The azo dyes I are incorporated in an organic solvent, such asisobutanol, methyl ethyl ketone, methylene chloride, chlorobenzene,toluene, tetrahydrofuran or a mixture thereof, together with one or morebinders and possibly further assistants such as release agents orcrystallization inhibitors to form a printing ink in which the dyes arepreferably present in a molecularly dispersed, i.e. dissolved, form. Theprinting ink is then applied to an inert support and dried.

Suitable binders for the use of the azo dyes I according to the presentinvention are all materials which are soluble in organic solvents andwhich are known to be suitable for thermotransfer printing, e.g.cellulose derivatives such as methylcellulose, hydroxypropylcellulose,cellulose acetate or cellulose acetobutyrate, but in particularethylcellulose and ethylhydroxyethylcellulose, starch, alginates, alkydresins and vinyl resins such as polyvinyl alcohol orpolyvinylpyrrolidone but in particular polyvinyl acetate and polyvinylbutyrate. It is also possible to use polymers and copolymers ofacrylates and derivatives thereof, such as polyacrylic acid, polymethylmethacrylate or styrene/acrylate copolymers, polyester resins, polyamideresins, polyurethane resins or natural resins such as gum arabic.

It is frequently advisable to use mixtures of these binders, for examplemixtures of ethylcellulose and polyvinyl butyrate in a weight ratio of2:1.

The weight ratio of binder to dye is in general from 8:1 to 1:1,preferably from 5:1 to 2:1.

Suitable assistants are for example release agents based onperfluorinated alkylsulfonamidoalkyl esters or silicones as described inEP-A-227,092 and EP-A-192,435, and in particular organic additives whichstop the transfer dyes from crystallizing out in the course of storageor heating of the inked ribbon, for example cholesterol or vanillin.

Inert support materials are for example tissue, blotting or parchmentpaper and films made of heat resistant plastics such as polyesters,polyamides or polyimides, which films may also be metal coated.

The inert support may additionally be coated on the side facing thethermal printing head with a lubricant in order that adhesion of thethermal printing head to the support material may be prevented. Suitablelubricants are for example silicones or polyurethanes as described inEP-A-216,483.

The thickness of the dye transfer is in general from 3 to 30 μm,preferably from 5 to 10 μm.

The substrate to be printed, e.g. paper, must in turn be coated with aplastic which receives the dye during the printing process. It ispreferable to use for this purpose polymeric materials whose glasstransition temperatures T_(g) are within the range from 50° to 100° C;,e.g. polycarbonates and polyesters. Details may be found inEP-A-227,094, EP-A-133,012, EP-A-133,011, JP-A-199,997/1986 orJP-A-283,595/1986.

The process according to the present invention is carried out using athermal printing head which is heatable to above 300° C., so that dyetransfer takes not more than 15 msec.

EXAMPLES

First, transfer sheets (donors) were produced from a polyester sheetfrom 6 to 10 μm in thickness coated with an approximately 5 μm thicktransfer layer of a binder B which in each case contained about 0.25 gof azo dye I. The weight ratio of binder to dye was in each case 4:1,unless otherwise stated in the Tables below.

The substrate (receiver) to be printed was paper about 120 μm inthickness which had been coated with a layer of plastic 8 μm inthickness (Hitachi Color Video Print Paper).

Donor and receiver were placed on top of one another with the coatedfronts next to each other, then wrapped in aluminum foil and heatedbetween two hotplates at 70°-80° C. for 2 minutes. This operation wasrepeated three times with similar samples at a temperature within therange from 80° to 120° C., the temperature being increased each time.

The amount of dye diffusing into the plastics layer of the receiver inthe course of transfer is proportional to the optical density determinedphotometrically as absorbance A after each heating phase at theabovementioned temperatures.

The plot of the logarithm of the measured absorbances A against thecorresponding reciprocal of the absolute temperature is a straight linefrom whose slope it is possible to calculate the activation energyΔE.sub.λ for the transfer experiment: ##EQU1##

From the plot it is additionally possible to discern the temperature T*at which the absorbance attains the value 1, i.e. at which thetransmitted light intensity is one tenth of the incident lightintensity. The lower the temperature T*, the better the thermaltransferability of the particular dye.

The Tables which follow list the azo dyes I which were studied inrespect of their thermal transfer characteristics together with theirabsorption maxima λ_(max) [nm]. The λ_(max) values were measured inmethylene chloride or the stated solvent.

In addition, they list the particular binder B used employing thefollowing abbreviations: EC=ethylcellulose, PVB=polyvinyl butyrate,MIX=EC:PVB=2:1, and VY=vylon.

If the abovementioned parameters R* [° C.] and ΔE, [kJ/mol] weremeasured, the values found are likewise stated.

                                      TABLE 1                                     __________________________________________________________________________     ##STR16##                                                  IIIa              Ex.                                                                              R.sup.1                                                                           R.sup.2    R.sup.3                                                                          R.sup.5          R.sup.6                                                                            λ.sub.max                                                                   Bnm]                                                                             T*[°C.]                                                                     ΔE.sub.τ                                                             [kJ/mol]             __________________________________________________________________________    1  Ph  (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                          CN               H    494  EC 104  42                    2  Ph  (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                           ##STR17##       NO.sub.2                                                                           544  MS  90  71                    __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________     ##STR18##                                                  IIIb              Ex.                                                                              R.sup.2    R.sup.3                                                                          R.sup.5                                                                          R.sup.6                                                                           R.sup.7                                                                           R.sup.11                                                                            R.sup.12                                                                         R.sup.12'                                                                           λ.sub.max                                                                   Bnm]                                                                             T*[°C.]                                                                     ΔE.sub.τ                                                              [kJ/mol]            __________________________________________________________________________    3  C.sub.2 H.sub.5                                                                          R.sup.2                                                                          Cl CN  Cl  OCH.sub.3                                                                           H  OCH.sub.3                                                                           584  EC 96   84                    4  (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                          H  H   H   Br    H   H    538  MS 97   76                    5  (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                          H  H   H   Br    Br H     492  EC 106  84                    __________________________________________________________________________

    TABLE 3      ##STR19##      IIIc  Ex. R.sup.1 R.sup.2 R.sup.3 R.sup.8 R.sup.10 λ.sub.max     [nm] B T*[°C.] ΔE.sub.τ      [kJ/mol]                          6 Cyclohexyl C.sub.2 H.sub.5 R.sup.2     CH.sub.3 CN 550 MIX 90 65  7 Cyclohexyl C.sub.2 H.sub.5 R.sup.2 CH.sub.3 C     OOCH.sub.3 .sup. 545.sup.a -- -- --      8 Cyclohexyl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 COOCH.sub.3     .sup. 544.sup.a -- -- --  9 Cyclohexyl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 C     l COH .sup.      580.sup.a MIX 90 88        VY 90 58 10 Cyclohexyl (CH.sub.2).sub.2OCH.su     b.3 R.sup.2 Cl CHC(CN)COO.sub.4 H.sub.9 625 VY 99 54 11 Cyclohexyl     (CH.sub.2).sub.3OCH.sub.3 C.sub.2 H.sub.5 CH.sub.3 CN 551 MIX 92 77 12     Cyclohexyl (CH.sub.2).sub.3OCH.sub.3 C.sub.2 H.sub.5 Cl COH 572 MIX 92     66        VY 86 40 13 CH(CH.sub.3)CH.sub.3 C.sub.2 H.sub.5 R.sup.2     CH.sub.3 CN 547 EC 90 88 14 CH(CH.sub.3)CH.sub.3 C.sub.2 H.sub.5 R.sup.2 C     l COH 572 MIX 90 50 15 CH(CH.sub.3)CH.sub.3 C.sub.2 H.sub.5 R.sup.2     CH.sub.3 CN 547 -- -- -- 16 CH(CH.sub.3)CH.sub.3 C.sub.2 H.sub.5 R.sup.2 C     OOC.sub.2 H.sub.5 COOC.sub.2 H.sub.5 542 VY 135  50 17 CH(C.sub.2     H.sub.5)C.sub.4 H.sub.9 C.sub.2 H.sub.5 R.sup.2 Cl CHC(CN)COOC.sub.4     H.sub.9 608 MIX   90** 59 18 Ph C.sub.2 H.sub.5 R.sup.2 H NO.sub.2 623     -- -- -- 19 Ph C.sub.2 H.sub.5 R.sup.2 Cl Br 559 -- -- -- 20 Ph C.sub.2     H.sub.5 R.sup.2 Cl COH 602 -- -- -- 21 Ph C.sub.2 H.sub.5 R.sup.2     CH.sub.3 COOC.sub.2 H.sub.5 569 EC 132  64 22 Ph C.sub.2 H.sub.5 R.sup.2 O    C     .sub.2 H.sub.5 COH 598 -- -- -- 23 Ph C.sub.2 H.sub.5 R.sup.2 COOC.sub.2     H.sub.5 COOC.sub.2 H.sub.5 573 VY 100       52 24 Ph (CH.sub.2).sub.3OCH.sub.3 C.sub.2 H.sub.5 Cl COH 574 VY 81 23     25 Ph (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5     CH.sub.3 COOCH.sub.3 .sup.      576.sup.a -- -- -- 26 Ph (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3     C.sub.2 H.sub.5 Cl COH .sup.      606.sup.a -- -- -- 27 Ph (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3     C.sub.3 H.sub.7 CH.sub.3 CN .sup.      582.sup.a MIX 91 64 28 Ph (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3     C.sub.3      H.sub.7 Cl COH 633 MIX 91 60 29 Ph [(CH.sub.2).sub.2O].sub.2C.sub.2     H.sub.5 (CH.sub.2).sub.3OCH.sub.3 Cl CHC(CN)COOC.sub.4 H.sub.9 644 EC     130  76 30 Ph [(CH.sub.2).sub.2O].sub.3C.sub.2 H.sub.5 C.sub.2 H.sub.5     Cl COH 601 EC* 94 73 31 Ph [(CH.sub.2).sub.2O].sub.3C.sub.2 H.sub.5     C.sub.2 H.sub.5 Cl CHC(CN)COOC.sub.4 H.sub.9 653 MIX 106  46 32 Ph     [(CH.sub.2).sub.2O].sub.3C.sub.2 H.sub.5 (CH.sub.2).sub.3OCH.sub.3 Cl     CHC(CN)COOC.sub.4 H.sub.9 648 MIX 122       67 33 Ph (CH.sub.2).sub.2O[(CH.sub.2).sub.2O].sub.2CH.sub.3 C.sub.2     H.sub.5 CH.sub.3 CN .sup.      581.sup.a -- -- -- 34 Ph (CH.sub.2).sub.3O[(CH.sub.2).sub.2O].sub.2CH.su     b.3 C.sub.2 H.sub.5 CH.sub.3 CN .sup.      583.sup.a -- -- -- 35 Ph CH.sub.2[(CH.sub.2).sub.2O].sub.2 CH.sub.3     C.sub.2 H.sub.5 CH.sub.3 COOC.sub.2 H.sub.5 .sup. 575.sup.a -- -- -- 36     Ph CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3 C.sub.2 H.sub.5 CH.sub.3    C     COOH.sub.3 .sup.      575.sup.a -- -- -- 37 Ph CH.sub.2[(CH.sub.2).sub.2O].sub.2C.sub.2     H.sub.5 C.sub.2 H.sub.5 CH.sub.3 COOC.sub.2 H.sub.5 .sup. 575.sup.a --     -- -- 38 Ph-4-OCH.sub.3 C.sub.2 H.sub.5 R.sup.2 COOC.sub.2 H.sub.5     COOC.sub.2 H.sub.5 591 EC 120  50 39 Ph-3-SO.sub.2N(CH.sub.3).sub.2     C.sub.2      H.sub.5 R.sup.2 Cl COH 595 -- -- -- 40 Ph-3-SO.sub.2N(CH.sub.3).sub.2     (CH.sub.2).sub.2OCH.sub.3 R.sup.2 Cl COH 596 -- -- -- 41 Ph-3-SO.sub.2N[(     CH.sub.2).sub.2OCH.sub.3 ].sub.2 C.sub.2 H.sub.5 R.sup.2 CH.sub.3     COOCH.sub.3 586 -- -- -- 42 CH.sub.2Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2 C     H.sub.3 COOCH.sub.3 .sup. 540.sup.a VY 94 51 43 CH.sub.2OPh C.sub.2     H.sub.5 R.sup.2 CH.sub.3 CN .sup. 543.sup.a MIX 88 72 44 Thien-3-yl     C.sub.2 H.sub.5 R.sup.2 CH.sub.3 COOCH.sub.3 .sup. 582.sup.a -- -- -- 45     Thien-2-yl C.sub.2 H.sub.5 R.sup.2 COOC.sub.4 H.sub.9 COOC.sub.4 H.sub.9     600 MIX 94 80 46 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5     CH.sub.3 COOC.sub.2 H.sub.5 .sup. 597.sup.a -- -- -- 47 Thien-2-yl     (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3  CN 599 -- -- -- 48 Thien-2-yl      (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 COOCH.sub.3 589 -- -- -- 49     Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 Cl COH 631 -- -- -- 50     Thien-3-yl (CH.sub.2).sub.3OCH.sub.3 C.sub.2      H.sub.5 CH.sub.3 COOCH.sub.3 .sup. 583.sup.a -- -- -- 51 Thien-2-yl     (CH.sub.2).sub.3OCH.sub.3 C.sub.2 H.sub.5 CH.sub.3 COOC.sub.2 H.sub.5     .sup. 598.sup.a -- -- -- 52 Thien-2-yl (CH.sub.2).sub.3OCH.sub.3 C.sub.2     H.sub.5 Cl COH .sup.      638.sup.a -- -- -- 53 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.su     b.3 C.sub.2 H.sub.5 CH.sub.3 COOCH.sub.3 .sup. 599.sup.a -- -- -- 54     Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5 Cl C     OH .sup.      639.sup.a -- -- -- 55 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.su     b.3 C.sub.3      H.sub.7 Cl COH 636 MIX 91 59 56 Thien-3-yl (CH.sub.2).sub.3O(CH.sub.2).s     ub.2OCH.sub.3 C.sub.3 H.sub.7 Cl COH .sup. 619.sup.a -- -- -- 57     Furan-2-yl C.sub.2 H.sub.5 R.sup.2 CH.sub.3 CN .sup. 605.sup.a -- -- --     58 Furan-2-yl C.sub.2 H.sub.5 R.sup.2 CH.sub.3 COOCH.sub.3 .sup.     596.sup.a -- -- -- 59 Furan-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2     CH.sub.3 COOCH.sub.3 .sup.      594.sup.a -- -- -- 60 Furan-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.su     b.3  C.sub.3 H.sub.7 Cl COH .sup. 635.sup.a -- -- -- 61 Pyrid-3-yl     C.sub.2 H.sub.5 R.sup.2 Cl COH .sup.     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid     *weight ratio of binder:dye = 2:1

                                      TABLE 3a                                    __________________________________________________________________________     ##STR20##                                                  IIIc                                                                          ΔE.sub..                                                                tau.                                                                 λ.sub.max                                                                    T* [kJ/              Ex.                                                                              R.sup.1  R.sup.2        R.sup.3                                                                            R.sup.8                                                                           R.sup.9  R.sup.10                                                                            [nm]                                                                             B  [°C.]                                                                     mol]              __________________________________________________________________________    62 Ph       CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3                                                    C.sub.2 H.sub.5                                                                    Cl  COOCH.sub.3                                                                            COH   598.sup.a                                                                        -- -- --                63 Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                    C.sub.2 H.sub.5                                                                    CH.sub.3                                                                          COO CH.sub.3                                                                           CN    577.sup.                                                                         VY  82                                                                              32                64 Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                    C.sub.2 H.sub.5                                                                    Cl  COOCH.sub.3                                                                            COH   611.sup.a                                                                        -- -- --                65 Ph       (CH.sub.2).sub.2OCH.sub.3                                                                    R.sup.2                                                                            CH.sub.3                                                                          COOC.sub.2 H.sub.5                                                                     CN    562.sup.a                                                                        -- -- --                66 Ph       (CH.sub.2).sub.3OCH.sub.3                                                                    C.sub.3 H.sub.7                                                                    CH.sub.3                                                                          COOC.sub.2 H.sub.5                                                                     CN    589.sup.a                                                                        -- -- --                67 Ph-4-OCH.sub.3                                                                         (CH.sub.2).sub.2OCH.sub.3                                                                    R.sup.2                                                                            CH.sub.3                                                                          COOC.sub.2 H.sub.5                                                                     CN    567.sup.                                                                         VY 107                                                                              59                68 Thien-2-yl                                                                             CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3                                                    C.sub.2 H.sub.5                                                                    CH.sub.3                                                                          COOC.sub.2 H.sub.5                                                                     CN    577.sup.                                                                         VY 105                                                                              45                __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                 

                                      TABLE 4                                     __________________________________________________________________________     ##STR21##                                                  IIIe                                                                          ΔE.sub..                                                                tau.                                                                 λ.sub.max                                                                    T* [kJ/              Ex. R.sup.1                                                                         R.sup.2          R.sup.3                                                                            R.sup.8  R.sup.10      [nm]                                                                             B  [°C.]                                                                     mol]              __________________________________________________________________________    69 Ph (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            H        NO.sub.2      .sup. 595.sup.a                                                                  -- -- --                70 Ph (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            Cl       COH           581                                                                              -- -- --                71 Ph (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup. 2                                                                           Cl       CHC(CN)COOC.sub.4 H.sub.9                                                                   637                                                                              VY 130                                                                              52                72 Thien-                                                                           C.sub.2 H.sub.5  R.sup.2                                                                            Cl       CHC(CN)COOC.sub.4 H.sub.9                                                                   631                                                                              VY 125                                                                              67                  3-yl                                                                        73 Thien-                                                                           C.sub.2 H.sub.5  R.sup.2                                                                            COOCH.sub.3                                                                            CN            581                                                                              -- -- --                  2-yl                                                                        74 Thien-                                                                           (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            H        NO.sub.2      626                                                                              -- -- --                  2-yl                                                                        75 Thien-                                                                           (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.3 H.sub.7                                                                    Cl       COH           593                                                                              -- -- --                  3-yl                                                                        __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                 

                                      TABLE 5                                     __________________________________________________________________________     ##STR22##                                                  IIIg                                                                          ΔE.sub..                                                                tau.                                                                 λ.sub.max                                                                    T* [kJ/              Ex.R.sup.1    R.sup.2          R.sup.3                                                                            R.sup.8    R.sup.9                                                                           [nm]                                                                             B  [°C.]                                                                     mol]              __________________________________________________________________________     76 CH(CH.sub.3)CH.sub.3                                                                    C.sub.2 H.sub.5  R.sup.2                                                                            (CH.sub.2).sub.2OCH.sub.3                                                                CN  522                                                                              EC*                                                                              63 69                 77 Cyclohexyl                                                                              C.sub.2 H.sub.5  R.sup.2                                                                            CH.sub.3   CN  520                                                                              MIX                                                                              85 97                                                                   .sup. 526.sup.a                                                                  VY 75 34                 78 Cyclohexyl                                                                              C.sub.2 H.sub.5  R.sup.2                                                                            Ph         CN  529                                                                              VY 89 24                 79 Cyclohexyl                                                                              C.sub.2 H.sub.5  R.sup.2                                                                            (CH.sub.2).sub.2OCH.sub.3                                                                CN  .sup. 528.sup.a                                                                  -- -- --                 80 Cyclohexyl                                                                              (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            CH.sub.3   CN  521                                                                              VY 75 42                 81 Cyclohexyl                                                                              (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            Ph         CN  524                                                                              MIX                                                                              100                                                                              80                 82 Cyclohexyl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    CH.sub.3   CN  523                                                                              VY 72 38                 83 Cyclohexyl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                          CN  520                                                                              VY 75 37                 84 Cyclohexyl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    Ph         CN  529                                                                              VY 84 44                 85 Cyclohexyl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    (CH.sub.2).sub.2OCH.sub.3                                                                CN  524                                                                              VY 72 33                 86 Cyclohexyl                                                                              [(CH.sub.2).sub.2 O].sub.2CH.sub.3                                                             R.sup.2                                                                            Thien-2-yl CN  .sup. 587.sup.a                                                                  -- -- --                 87 Cyclohexyl                                                                              CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3                                                      C.sub.3 H.sub.7                                                                    Ph         CN  531                                                                              VY 88 38                 88 Ph        C.sub.2 H.sub.5  R.sup.2                                                                            (CH.sub.2).sub.2OCH.sub.3                                                                CN  548                                                                              VY 89 53                 89 Ph        C.sub.2 H.sub.5  R.sup.2                                                                            Ph-4-SPh   CN  556                                                                              EC 118                                                                              53                 90 Ph-3-OCH.sub.3                                                                          C.sub.2 H.sub.5  R.sup.2                                                                            Thien-2-yl CN  572                                                                              -- -- --                 91 Ph-3-SO.sub.2N(CH.sub.3).sub.2                                                          (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            (CH.sub.2).sub.3OCH.sub.3                                                                CN  548                                                                              EC*                                                                              89 32                 92 CH.sub.2OPh                                                                             (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            CH.sub.3   CN  .sup. 531.sup.a                                                                  -- -- --                 93 Furan-2-yl                                                                              C.sub.2 H.sub.5  R.sup.2                                                                            CH.sub.3   CN  .sup. 578.sup.a                                                                  -- -- --                 94 Furan-2-yl                                                                              C.sub.2 H.sub.5  R.sup.2                                                                            (CH.sub.2).sub.2OCH.sub.3                                                                CN  .sup. 578.sup.a                                                                  -- -- --                 95 Thien-2-yl                                                                              (CH.sub.2).sub.2OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    CH(CH.sub.3)CH.sub.3                                                                     CN  .sup. 579.sup.a                                                                  -- -- --                 96 Thien-2-yl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    C.sub.2 H.sub.5                                                                          CN  .sup. 581.sup.a                                                                  -- -- --                 97 Thien-2-yl                                                                              (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.3 H.sub.7                                                                    C.sub.2 H.sub.5                                                                          CN  .sup. 581.sup.a                                                                  -- -- --                 98 Thien-3-yl                                                                              (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.2 H.sub.5                                                                    CH.sub.3   CN  .sup. 562.sup.a                                                                  -- -- --                 99 Thien-2-yl                                                                              CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3                                                      C.sub. 2 H.sub.5                                                                   C.sub.2 H.sub.5                                                                          CN  .sup. 582.sup.a                                                                  -- -- --                100 Thien-2-yl                                                                              CH.sub.2[(CH.sub.2).sub.2O].sub.2CH.sub.3                                                      C.sub.3 H.sub.7                                                                    C.sub.2 H.sub.5                                                                          CN  .sup. 580.sup.a                                                                  -- -- --                101 CH(CH.sub.3)CH.sub.3                                                                    C.sub.2 H.sub.5  R.sup.2                                                                            CH.sub.3   SCN 512                                                                              EC 87 99                102 Ph        C.sub.2 H.sub.5  R.sup.2                                                                            CH.sub.3   SCN 540                                                                              -- -- --                103 Ph        (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            CH.sub.3   SCN 538                                                                              EC 90 57                Thien-2-yl    C.sub.2 H.sub.5  R.sup.2                                                                            CH.sub.3   SCN 562                                                                              EC 88 47                __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                      *weight ratio of binder:dye = 2:1                                        

                                      TABLE 6                                     __________________________________________________________________________     ##STR23##                                 IIIh                               Ex.                                                                              R.sup.1  R.sup.2          R.sup.3                                                                            X   X' λ.sub.max                     __________________________________________________________________________                                             [nm]                                 105                                                                              Ph       (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            H   H  573.sup.a                            106                                                                              Ph       (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            Cl  H  579.sup.a                            107                                                                              Ph       (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.2 H.sub.5                                                                    H   H  574.sup.a                            108                                                                              Ph       (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.3 H.sub.7                                                                    NO.sub.2                                                                          H  629.sup.a                            109                                                                              Ph-4-OCH.sub.3                                                                          (CH.sub.2).sub.2OCH.sub.3                                                                     R.sup.2                                                                            Cl  H  594.sup.a                            110                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            H   H  594.sup.a                            111                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.2OCH.sub.3                                                                      R.sup.2                                                                            Cl  H  602.sup.a                            112                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    H   H  597.sup.a                            113                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                      C.sub.2 H.sub.5                                                                    Cl  H  605.sup.a                            114                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                      R.sup.2                                                                            Cl  H  606.sup.a                            115                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.2 H.sub.5                                                                    H   H  598.sup.a                            116                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.3 H.sub.7                                                                    Cl  H  598.sup.a                            117                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.3 H.sub.7                                                                    H   Cl 606.sup.a                            __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                 

                                      TABLE 7                                     __________________________________________________________________________     ##STR24##                                       IIIi                         Ex.                                                                              R.sup.1                                                                           R.sup.2          R.sup.3                                                                            Y   λ.sub.max [nm]                                                              B  T*[°C.]                                                                    ΔE.sub.τ  [kJ/mol]     __________________________________________________________________________    118                                                                              CH.sub.3                                                                          C.sub.2 H.sub.5  R.sup.2                                                                            CN  591  EC*                                                                              130 44                               119                                                                              Ph  C.sub.2 H.sub.5  R.sup.2                                                                            H   583  -- --  --                               120                                                                              Ph  (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3                                                     C.sub.3 H.sub.7                                                                    CN  .sup. 622.sup.a                                                                    -- --  --                               __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                      *weight ratio of binder:dye = 2:1                                        

                                      TABLE 8                                     __________________________________________________________________________     ##STR25##                               IIIk                                 Ex.                                                                              R.sup.1                                                                             R.sup.2    R.sup.3                                                                         R.sup.8                                                                          λ.sub.max [nm]                                                              B  T*[°C.]                                                                    ΔE.sub.τ [kJ/mol]              __________________________________________________________________________    121                                                                              PH    C.sub.2 H.sub.5                                                                          R.sup.2                                                                         Ph 531.sup.                                                                           EC 94  68                                       122                                                                              Ph    (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                         Ph 533.sup.a                                                                          -- --  --                                       123                                                                              Cyclohexyl                                                                          (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                         Ph 508.sup.a                                                                          -- --  --                                       124                                                                              Thien-2-yl                                                                          (CH.sub.2).sub.2OCH.sub.3                                                                R.sup.2                                                                         Ph 556.sup.a                                                                          -- --  --                                       __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                 

                                      TABLE 9                                     __________________________________________________________________________     ##STR26##                                            IIIl                    Ex.                                                                              R.sup.1                                                                             R.sup.2    R.sup.3                                                                         R.sup.8        λ.sub.max [nm]                                                              B  T*[°C.]                                                                     ΔE.sub.τ                                                            [kJ/mol]                    __________________________________________________________________________    125                                                                              Ph    C.sub.2 H.sub.5                                                                          R.sup.2                                                                         S(CH.sub.2).sub.2COOCH.sub.3                                                                 535  EC 110  72                          126                                                                              Ph    C.sub.2 H.sub.5                                                                          R.sup.2                                                                         S(CH.sub.2).sub.2CN                                                                          536  EC 103  47                          127                                                                              Ph    C.sub.2 H.sub.5                                                                          R.sup.2                                                                         SCH.sub.3      533  -- --   --                          128                                                                              Ph    C.sub.2 H.sub.5                                                                          R.sup.2                                                                         CH.sub.3       524  -- --   --                          129                                                                              Ph    (CH.sub. 2).sub.2OCH.sub.3                                                               R.sup.2                                                                         S(CH.sub.2).sub.2COOCH.sub.3                                                                 535  MIX                                                                               87  71                          130                                                                              Cyclohexyl                                                                          C.sub.2 H.sub.5                                                                          R.sup.2                                                                         S(CH.sub.2).sub.2COOCH.sub.3                                                                 .sup. 519.sup.a                                                                    -- --   --                          131                                                                              Cyclohexyl                                                                          C.sub.2 H.sub.5                                                                          R.sup.2                                                                         SCH.sub.3      .sup. 518.sup.a                                                                    -- --   --                          132                                                                              Thien-2-yl                                                                          C.sub.2 H.sub.5                                                                          R.sup.2                                                                         S(CH.sub.2).sub.2COOCH.sub.3                                                                 558  VY  93  61                          133                                                                              Thien-2-yl                                                                          C.sub.2 H.sub.5                                                                          R.sup.2                                                                         S(CH.sub.2).sub.2CN                                                                          560  EC 105  42                          134                                                                              Thien-2-yl                                                                          C.sub.2 H.sub.5                                                                          R.sup.2                                                                         SCH.sub.3      557  EC 126  62                          __________________________________________________________________________     .sup.a solvent 9:1 dimethylformamide/glacial acetic acid                      *weight ratio of binder:dye = 2:1                                        

                                      TABLE 10                                    __________________________________________________________________________     ##STR27##                                  IIIm                              Ex.                                                                              R.sup.1                                                                             R.sup.2                                                                            R.sup.3                                                                         R.sup.18                                                                             R.sup.19                                                                          λ.sub.max [nm]                                                              B  T*[°C.]                                                                     ΔE.sub.τ  [kJ/mol]          __________________________________________________________________________    135                                                                              Ph    C.sub.2 H.sub.5                                                                    R.sup.2                                                                         CN     Ph  567  MIX                                                                              106  37                                    136                                                                              Thien-2-yl                                                                          C.sub.2 H.sub.5                                                                    R.sup.2                                                                         CONH.sub.2                                                                           CH.sub.3                                                                          573  -- --   --                                    __________________________________________________________________________

The azo dyes I listed in the Tables below are likewise suitable forthermotransfer printing.

    TABLE 11      ##STR28##      IIIg      Ex. R.sup.1 R.sup.2 R.sup.3 R.sup.8 R.sup.9 Hue                     137 P     h (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 H red 138 Ph (CH.sub.2).sub.     2OCH.sub.3 R.sup.2 CH.sub.3 Cl red 139 Ph (CH.sub.2).sub.2OCH.sub.3     R.sup.2 CH.sub.3 Br red 140 Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2     CH.sub.3 CN violet 141 Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 SCN     violet 142 Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2 C.sub.2 H.sub.5 CN     violet 143 Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH(CH.sub.3)CH.sub.3 CN     violet 144 Ph (CH.sub.2).sub.2OCH.sub.3 R.sup.2 (CH.sub.2).sub.2OC.sub.2     H.sub.5 CN bluish red 145 Ph (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).sub.2OC     H.sub.3 CH.sub.3 SCN violet 146 Ph (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).s     ub.2OCH.sub.3 Ph CN violet 147 Ph (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).su     b.2OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3 CN violet 148 Ph (CH.sub.2).sub.3OC     H.sub.3 C.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN violet 149 Ph     (CH.sub.2).sub.3OC.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3 CN violet     150 Ph (CH.sub.2).sub.3OC.sub.2      H.sub.5 CH.sub.3 (CH.sub.2).sub.2OCH.sub.3 CN violet 151 Ph (CH.sub.2).s     ub.3O(CH.sub.2).sub.2OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3 Ph CN violet     152 Ph (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3 (CH.sub.2).sub.3OCH.sub     .3 Ph CN violet 153 Ph [(CH.sub.2).sub.2O].sub.2CH.sub.3 (CH.sub.2).sub.2O    C     H.sub.3 Ph CN violet 154 Ph [(CH.sub.2).sub.2O].sub.2CH.sub.3 CH.sub.3     (CH.sub.2).sub.2OCH.sub.3 CN violet 155 Ph [(CH.sub.2).sub.2O].sub.2CH.su     b.3 C.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN violet 156 Ph [(CH.sub.2).sub.2O].s     ub.2C.sub.2 H.sub.5 (CH.sub.2).sub.3OCH.sub.3 CH.sub.2Ph CN violet 157      Ph [(CH.sub.2).sub.2O].sub.3CH.sub.3 (CH.sub.2).sub.3OCH.sub.3 Ph CN     violet 158 Ph-4-Cl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 (CH.sub.2).sub.2OCH.     sub.3 CN violet 159 Ph-4-Cl [(CH.sub.2).sub.2O].sub.2CH.sub.3 C.sub.2     H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN violet 160 Ph-4-OCH.sub.3 (CH.sub.2)     .sub.2OCH.sub.3 C.sub.2 H.sub.5 CH.sub.3 CN violet 161 Ph-4-OCH.sub.3     (CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN     violet 162 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 SCN     violet 163 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 CH.sub.3 CN     reddish blue 164 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 C.sub.2     H.sub.5 CN reddish blue 165 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3 R.sup.2 C     .sub.3 H.sub.7 CN reddish blue 166 Thien-2-yl (CH.sub.2).sub.2OCH.sub.3     R.sup.2 CH(CH.sub.3)CH.sub.3 CN reddish blue 167 Thien-2-yl (CH.sub.2).su     b.3OCH.sub.3 R.sup.2 (CH.sub.2).sub.2OCH.sub.3 CN navy 168 Thien-2-yl     (CH.sub.2).sub.3OCH.sub.3 R.sup.2 (CH.sub.2).sub.2OC.sub.2 H.sub.5 CN     navy 169 Thien-2-yl (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3     CH.sub.3 SCN reddish blue 170 Thien-2-yl (CH.sub.2).sub.3OCH.sub.3     (CH.sub.2).sub.2OCH.sub.3 Ph CN reddish blue 171 Thien-2-yl (CH.sub.2).su     b.3OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3 Ph SCN reddish blue 172 Thien-2-yl      (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).sub.2OCH.sub.3 (CH.sub.2).sub.2OCH.     sub.3 CN navy 173 Thien-2-yl (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).sub.2OC     H.sub. 3 (CH.sub.2).sub.2OC.sub.2 H.sub.5 CN navy 174 Thien-2-yl     (CH.sub.2).sub.3OCH.sub.3 (CH.sub.2).sub.2OC.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 175 Thien-2-yl (CH.sub.2).sub.     3OCH.sub.3 (CH.sub.2).sub.2OC.sub.2 H.sub.5 Thien-2-yl CN blue 176     Thien-2-yl (CH.sub.2).sub.3OCH.sub.3 C.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 177 Thien-2-yl (CH.sub.2).sub.     3OC.sub.2 H.sub.5 (CH.sub.2).sub.3OCH.sub.3 Thien-3-yl CN blue 178     Thien-2-yl (CH.sub.2).sub.3OC.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3     (CH.sub.2).sub.2OCH.sub.3 CN navy      179 Thien-2-yl (CH.sub.2).sub.3OC.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3      ##STR29##      CN reddish blue  180 Thien-2-yl (CH.sub.2).sub.3O C.sub.2 H.sub.5     (CH.sub.2).sub.2OC.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 181     Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5     CH.sub.3 SCN bluish violet 182 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub     .2OCH.sub.3 C.sub.2      H.sub.5 Ph CN reddish blue 183 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).su     b.2OCH.sub.3 C.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 184     Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.sub.3 C.sub.2 H.sub.5     Thien-2-yl CN blue 185 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OCH.su     b.3 C.sub.3      H.sub.7 CH(CH.sub.3)CH.sub.3 CN navy 186 Thien-2-yl (CH.sub.2).sub.3O(CH     .sub.2).sub.2OCH.sub.3 C.sub.3 H.sub.7 Ph CN reddish blue 187 Thien-2-yl (     CH.sub.2).sub.3O(CH.sub.2).sub.2 OCH.sub.3 C.sub.3      H.sub.7 (CH.sub.2).sub.2OCH.sub.3 CN navy 188 Thien-2-yl (CH.sub.2).sub.     3O(CH.sub.2).sub.2OCH.sub.3 C.sub.3 H.sub.7 (CH.sub.2).sub.2OC.sub.2     H.sub.5 CN navy 189 Thien-2-yl (CH.sub.2).sub.3O(CH.sub.2).sub.2OC.sub.2     H.sub.5 C.sub.2 H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 190 Thien-2-yl     [(CH.sub.2).sub.2O].sub.2CH.sub.3 (CH.sub.2).sub.2OCH.sub.3 Thien-2-yl     CN reddish blue 191 Thien-2-yl [(CH.sub.2).sub.2O].sub.2CH.sub.3     (CH.sub.2).sub.2OCH.sub.3 Thien-3-yl CN blue 192 Thien-2-yl [(CH.sub.2).s     ub.2O].sub.2CH.sub.3 (CH.sub.2).sub.3OCH.sub.3 Ph CN reddish blue 193     Thien-2-yl [(CH.sub.2).sub.2O].sub.2CH.sub.3 C.sub.2      H.sub.5 (CH.sub.2).sub.2OCH.sub.3 CN navy 194 Thien-2-yl [(CH.sub.2).sub     .2 O].sub.2CH.sub.3 C.sub.2 H.sub.5 Thien-3-yl CN blue 195 Thien-2-yl     [(CH.sub.2).sub.2O].sub.2CH.sub.3 C.sub.3      H.sub.7 (CH.sub.2).sub.2OCH.sub.3 CN navy 196 Thien-2-yl [(CH.sub.2).sub     .2O].sub.2C.sub.2 H.sub.5 (CH.sub.2).sub.3OCH.sub.3 Ph CN reddish blue     197 Thien-2-yl [(CH.sub.2).sub.2O].sub.2C.sub.2                          C      H.sub.5 (CH.sub.2).sub.3OH.sub.3 Pyrid-3-yl CN reddish blue 198     Thien-2-yl [(CH.sub.2).sub.2O].sub.3CH.sub.3 (CH.sub.2).sub.3OCH.sub.3     Ph CN reddish blue 199 Thien-2-yl [(CH.sub.2).sub.2O].sub.3CH.sub.3     (CH.sub.2).sub.2OCH.sub.3 Thien-2-yl CN reddish blue 200 Thien-2-yl     [(CH.sub.2).sub.2O].sub.3CH.sub.3 (CH.sub.2).sub.2OCH.sub.3 Thien-3-yl     CN reddish blue 201 Thien-2-yl [(CH.sub.2).sub.2O].sub.3CH.sub.3 C.sub.2     H.sub.5 Ph  CN reddish blue 202 Thien-2-yl [(CH.sub.2).sub.2O].sub.3CH.su     b.3 C.sub.2      H.sub.5 Thien-2-yl CN blue 203 Thien-2-yl [(CH.sub.2).sub.2O].sub.3CH.su     b.3 C.sub.2      H.sub.5 Thien-3-yl CN blue

                                      TABLE 12                                    __________________________________________________________________________     ##STR30##                                            IIIl                    Ex.                                                                              R.sup.1  R.sup.2     R.sup.3    R.sup.8        Hue                         __________________________________________________________________________    204                                                                              Ph       (CH.sub.2).sub.2OCH.sub.3                                                                 R.sup.2    SCH.sub.3      reddish violet              205                                                                              Ph       (CH.sub.2).sub.3OCH.sub.3                                                                 (CH.sub.2).sub.2OCH.sub.3                                                                SCH.sub.3      violet                      206                                                                              Ph       (CH.sub.2).sub.3OCH.sub.3                                                                 C.sub.2 H.sub.5                                                                          S(CH.sub.2).sub.2COOCH.sub.3                                                                 violet                      207                                                                              Ph       [(CH.sub.2).sub.2O].sub.2CH.sub.3                                                         Ph         SCH.sub.3      violet                      208                                                                              Ph       [(CH.sub.2).sub.2O].sub.2C.sub.2 H.sub.5                                                  Ph         SCH.sub.3      violet                      209                                                                               Ph-4-OCH.sub.3                                                                        (CH.sub.2).sub.3OCH.sub.3                                                                 (CH.sub.2).sub.2OCH.sub.3                                                                SCH.sub.3      violet                      210                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.2OCH.sub.3                                                                 R.sup.2    SCH.sub.3      reddish blue                211                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                 R.sup.2    SCH.sub.3      reddish blue                212                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                 (CH.sub.2).sub.2OCH.sub.3                                                                SC.sub.2 H.sub.5                                                                             reddish blue                213                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                 (CH.sub.2).sub.2OC.sub.2 H.sub.5                                                         SCH.sub.3      bluish violet               214                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OCH.sub.3                                                                 C.sub.2 H.sub.5                                                                          S(CH.sub.2).sub.2COOCH.sub.3                                                                 bluish violet               215                                                                              Thien-2-yl                                                                             (CH.sub.2).sub.3OC.sub.2 H.sub.5                                                          C.sub.2 H.sub.5                                                                          S(CH.sub.2).sub.2COOCH.sub.3                                                                 bluish violet               216                                                                              Thien-2-yl                                                                             [(CH.sub.2).sub.2O].sub.2CH.sub.3                                                         C.sub.2 H.sub.5                                                                          SCH.sub.3      bluish violet               217                                                                              Thien-2-yl                                                                             [(CH.sub.2).sub.2O].sub. 2C.sub.2 H.sub.5                                                 (CH.sub.2).sub.3OCH.sub.3                                                                SCH.sub.3      bluish violet               218                                                                              Thien-2-yl                                                                             [(CH.sub.2).sub.2O].sub.2C.sub.2 H.sub.5                                                  C.sub.2 H.sub.5                                                                          SCH.sub.3      bluish                      __________________________________________________________________________                                                      violet                  

We claim:
 1. A process comprising printing a substrate by thermotransferprinting with a transfer dye which is an azo dye of the general formulaI ##STR31## in which the substituents have the following meanings: R¹ ishydrogen;C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkyl substituted by phenyl orphenoxy; cyclohexyl, cyclohexyl substituted by C₁ -C₅ -alkyl, C₁ -C₅-alkoxy or halogen; phenyl, phenyl substituted by C₁ -C₅ -alkyl, C₁ -C₅-alkoxy, sulfonamido or halogen; thienyl, thienyl substituted by C₁ -C₅-alkyl or halogen; furanyl or pyridyl; a radical of the formula II

    [--W--O].sub.n --R.sup.4                                   II

where W is identical or different C₂ -C₆ -alkylene, n is from 1 to 6 andR⁴ is C₁ -C₄ -alkyl, phenyl or benzyl; phenyl or benzyl substituted byC₁ -C₄ -alkyl or C₁ -C₄ -alkoxy; R² and R³ are each hydrogen;alkyl,alkoxy, alkoxyalkyl, alkanoyloxyalkyl, alkoxycarbonyloxyalkyl,alkoxycarbonylalkyl, haloalkyl, hydroxyalkyl or cyanoalkyl, eachcontaining up to 15 carbon atoms; alkyl, alkoxy, alkoxyalkyl,alkanoyloxyalkyl, alkoxycarbonyloxyalkyl, alkoxycarbonylalkyl,haloalkyl, hydroxyalkyl or cyanoalkyl, each containing up to 15 carbonatoms, substituted by phenyl, C₁ -C₄ -alkylphenyl, C₁ -C₄ -alkoxyphenyl,halophenyl, benzyloxy, C₁ -C₄ -alkylbenzyloxy, C₁ -C₄ -alkoxybenzyloxy,halogenzyloxy, halogen, hydroxyl or by cyano; cyclohexyl, cyclohexylsubstituted by C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkoxy or halogen; phenyl,phenyl substituted by C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkoxy, benzyloxy orhalogen; a radical of the above-mentioned formula II; and D is theradical of a diazo component III

    D--NH.sub.2                                                III.


2. A process comprising transferring an azo dye or dyes by diffusionfrom a transfer to a plastic-coated substrate by means of a thermalprinting head, wherein said azo dye or dyes is or are of the formula I##STR32## in which the substituents have the following meanings: R¹ ishydrogen;C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkyl substituted by phenyl orphenoxy; cyclohexyl, cyclohexyl substituted by C₁ -C₅ -alkyl, C₁ -C₅-alkoxy or halogen; phenyl, phenyl substituted by C₁ -C₅ -alkyl, C₁ -C₅-alkoxy, sulfonamido or halogen; thienyl, thienyl substituted by C₁ -C₅-alkyl or halogen; furanyl or pyridyl;a radical of the formula II

    [--W--O].sub.n --R.sup.4                                   II

where W is identical or different C₂ -C₆ -alkylene, n is from 1 to 6 andR⁴ is C₁ -C₄ -alkyl, phenyl or benzyl; phenyl or benzyl substituted byC₁ -C₄ -alkyl or C₁ -C₄ -alkoxy; R² and R³ are each hydrogen;alkyl,alkoxy, alkoxyalkyl, alkanoyloxyalkyl, alkoxycarbonyloxyalkyl,alkoxycarbonylalkyl, haloalkyl, hydroxyalkyl or cyanoalkyl, eachcontaining up to 15 carbon atoms; alkyl, alkoxy, alkoxyalkyl,alkanoyloxyalkyl, alkoxycarbonyloxyalkyl, alkoxycarbonylalkyl,haloalkyl, hydroxyalkyl or cyanoalkyl, each containing up to 15 carbonatoms, substituted by phenyl, C₁ -C₄ -alkylphenyl, C₁ -C₄ -alkoxyphenyl,halophenyl, benzyloxy, C₁ -C₄ -alkylbenzyloxy, C₁ -C₄ -alkoxybenzyloxy,halogenzyloxy, halogen, hydroxyl or by cyano; cyclohexyl, cyclohexylsubstituted by C₁ -C₁₅ -alkyl, C₁ -C₁₅ -alkoxy or halogen; phenyl,phenyl substituted by C₁ -C₅ -alkyl, C₁ -C₅ -alkoxy, C₁ -C₁₅ -alkoxy,benzyloxy or halogen; a radical of the above-mentioned formula II; and Dis the radical of a diazo component III

    D--NH.sub.2                                                III.


3. A process as claimed in claim 2, wherein the azo dye or dyes has theformula Ia ##STR33## where the substituents have the following meanings:R^(1') is C₁ -C₈ -alkyl, C₁ -C₈ -alkyl substituted by phenyl orphenoxy;cyclohexyl; phenyl, phenyl substituted by C₁ -C₄ -alkyl, C₁ -C₄-alkoxy or chlorine; thienyl; a radical of the formula IIa

    [--(CH.sub.2).sub.3 --O].sub.p --(CH.sub.2).sub.2 --O].sub.q --R.sup.4'IIa

where p is 0 or 1, q is from 1 to 4, and R^(4') is C₁ -C₄ -alkyl, phenylor benzyl; R^(2') and R^(3') are each C₁ -C₁₂ -alkyl, C₁ -C₁₀ -alkoxy orC₁ -C₁₀ -cyanoalkyl or a radical of the above-mentioned formula IIa; andD' is the radical of a diazo component III of the aniline,phenylazoaniline, aminothiophene, phenylazoaminothiophene,aminothiazole, phenylazoaminothiazole, aminoisothiazole,aminobenzisothiazole, aminothiadiazole, aminoisothiadiazole,aminooxazole, aminooxadiazole, aminodiazole, aminotriazole oraminopyrrole series.